1. Field of Endeavor
The present invention relates to electron and ion beams and more particularly to a slit disk for modified faraday cup diagnostic for determining power density of electron and ion beams.
2. State of Technology
Electron beams are considered to be the most precise and clean method available for welding thick sections of materials. Unfortunately, electron beams suffer one critical deficiency, namely the repeatability of focusing the beam to a known power density. Without the ability to reliably reproduce the power distribution in an electron beam, weld quality cannot be guaranteed. This problem is exacerbated by the fact the many welds are made over a period of time and with different welding operators. Further complications arise when welds are developed on one machine than transferred to a different machine for production. An electron beam diagnostic method has been developed that enables the precise characterization of the power density distribution in high power electron beams. Such diagnostic method, which utilizes a modified Faraday cup, is exemplified by U.S. Pat. No. 5,382,895; U.S. Pat. No. 5,468,966; U.S. Pat. No. 5,554,926, U.S. Pat. No. 5,583,427; U.S. Pat. No. 6,300,755; and U.S. Pat. No. 7,288,772. This electron beam diagnostic method has been utilized, for example, to certify changes in electron beam welders, and is further described in J. W. Elmer et al, “Tomographic Imaging of Non-Circular and Irregular Electron Beam Power Density Distributions,” Welding Journal 72 (ii), p. 493-s, 1993.